On Fri, 5 Jan 2024 15:29:06 -0500 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx> > > Add the following APIs: > > tracefs_cpu_open_mapped() > tracefs_cpu_is_mapped() > tracefs_cpu_map() > tracefs_cpu_unmap() > > This will allow applications to choose to memory map the tracing ring buffer > if it is supported. This will improve the performance of tracefs_cpu_read() > and tracefs_cpu_read_buf(), but it is not done by default because it will > also hurt the performance of tracefs_cpu_buffered_read() and > tracefs_cpu_buffered_read_buf() as those use splicing, and with the ring > buffer memory mapped, the splice has to do a copy instead of a copyless > subbuffer move. > > Since this change relies on the libtraceevent APIs: > > kbuffer_dup() > kbuffer_subbuffer() > kbuffer_refresh() > kbuffer_read_buffer() > > Which are available after version 1.8, up the minimum version to 1.8. > > Note, the samples and utest rely on: > > tep_get_sub_buffer_data_size() > > which is in 1.8.1. > > Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> > --- > Changes since v1: https://lore.kernel.org/linux-trace-devel/20231228201100.78aae259@xxxxxxxxxxxxxxxxxxxx Updated the subject to say this is v2 :-p -- Steve
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